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United States Patent |
5,611,733
|
Jacob
,   et al.
|
March 18, 1997
|
Driveshaft with plunging part
Abstract
A driveshaft (1) for driving the wheels of a motor vehicle has two constant
velocity joints (2, 3) and a connecting shaft (4). The two constant
velocity joints (2, 3) are provided in the form of constant velocity fixed
joints. The plunging assembly required to change the longitudinal distance
(L) includes a plunging journal (21), formed onto the second joint part
(20) of the second constant velocity joint (3), and a plunging portion
(26) of the connecting shaft (4). The shaft (4) surrounds the plunging
journal (21) and is provided in the form of a tubular shaft. The
cross-section of the plunging portion (26) has the shape of a corrugated
shaft. Each outer corrugation peak, in the bore of the plunging portion
(26), includes a second running groove (29) positioned opposite a running
groove (22) in the plunging journal (21). Balls (23) are rollingly
arranged between the two running grooves (29, 22) and held by a cage (24).
By providing the plunging portion (26) of the connecting shaft (4) in the
form of a corrugated tube, it is possible to use less mass and to increase
the strength values as a result of the forming operation. At the same
time, the vibration behavior is improved.
Inventors:
|
Jacob; Werner (Frankfurt, DE);
Niederhufner; Manfred (Hanau, DE);
Heyne; Jurgen E. (Saarbrucken, DE)
|
Assignee:
|
Lohr & Bromkamp GmbH (Offenbach am Main, DE)
|
Appl. No.:
|
456177 |
Filed:
|
May 31, 1995 |
Foreign Application Priority Data
| Jun 03, 1994[DE] | 44 19 373.4 |
Current U.S. Class: |
464/140; 464/182; 464/906 |
Intern'l Class: |
F16C 003/03 |
Field of Search: |
464/179,178,182,140,141,906,139,168,167
403/164,165
|
References Cited
U.S. Patent Documents
1022909 | Apr., 1912 | Whitney | 464/167.
|
3203202 | Aug., 1965 | Broenyer | 464/167.
|
4075872 | Feb., 1978 | Geisthoff | 464/167.
|
4103514 | Aug., 1978 | Grosse-Entrump | 464/167.
|
Foreign Patent Documents |
1373752 | Aug., 1964 | FR.
| |
2164033 | Jul., 1973 | FR.
| |
2531374A1 | Feb., 1977 | DE.
| |
2540371A1 | Mar., 1977 | DE.
| |
2532674B2 | Mar., 1979 | DE.
| |
2801182B1 | Jun., 1979 | DE.
| |
2602074C2 | Oct., 1984 | DE.
| |
2737104C2 | Apr., 1985 | DE.
| |
4217322C1 | Dec., 1993 | DE.
| |
1340644 | Dec., 1973 | GB.
| |
Primary Examiner: Darling; John P.
Assistant Examiner: Dunn; Eileen A.
Attorney, Agent or Firm: Harness, Dickey & Pierce, P.L.C.
Claims
We claim:
1. A driveshaft for use in a driveline for driving the wheels of a motor
vehicle, comprising:
two constant velocity joints each having a first joint part with connecting
means to establish a connection with a driving or driven part of a
driveline, each constant velocity joint having a second joint part with
said two constant velocity joints being connected to one another by a
connecting shaft, and said two constant velocity joints being designed as
constant velocity fixed joints enabling only angular movements between
their first and second joint parts;
means for enabling changes in the distance between the connecting means,
said means for enabling change including a plunging journal and plunging
portion, said plunging journal is fast with one of the two second joint
parts and having a longitudinal axis identical to that of the associated
second joint part, said plunging journal, in its outer face, including a
plurality of circumferentially distributed first running grooves extending
parallel to the longitudinal axis, said connecting shaft is provided in
the form of a tube including said plunging portion which is movably
entered by the plunging journal, having a cross-section of the plunging
portion is corrugated, with an outer corrugation peak and an outer
corrugation valley alternating on the outer circumference and said bore of
the plunging portion including second running grooves which are positioned
opposite the first running grooves of the plunging journal and extend
parallel to the longitudinal axis and said second running grooves being
arranged in an outer corrugation peak, and after each first and second
running grooves, one of each forming a pair, receive a plurality of
rolling contact members arranged one behind the other along said running
grooves.
2. A driveshaft according to claim 1, wherein said plunging portion is
produced by a non-chip producing forming operation.
3. A driveshaft according to claim 2, wherein the plunging portion is
produced from a steel tube by hammering, rolling or drawing.
4. A driveshaft according to claim 1, wherein the rolling contact members
associated with all running grooves are held in a cage and said cage is
movable to a limited extent relative to the plunging journal and the
plunging portion along the longitudinal axis.
5. A driveshaft according to claim 1, wherein plunging portion is provided
with stops for limiting the movement of the rolling contact members and/or
a cage.
6. A driveshaft according to claim 5, wherein one of the stops form part of
an insert inserted plunging portion.
7. A driveshaft according to claim 6, wherein said insert is supported
against a shoulder formed as a result of a cross-sectional reduction in
the region of transition between said plunging portion and an adjoining
portion.
8. A driveshaft according to claim 1, wherein said plunging portion is
provided with a plunging stop for the plunging journal for limiting the
distance by which the plunging journal is inserted into the plunging
portion.
9. A driveshaft according to claim 8, wherein one of the plunging stops
form part of an insert of the plunging portion.
10. A driveshaft according to claim 1, wherein apart from the plunging
portion, the connecting shaft includes a connection portion for securing
to the second joint part of the other constant velocity joint.
11. A driveshaft according to claim 10, wherein said connecting shaft
includes a portion of transition between the plunging portion and the
connecting portion.
12. A driveshaft according to claim 11, wherein the cross-section of the
plunging portion is increased relative to that of the portion of
transition and/or said connecting portion.
13. A driveshaft according to claim 11, wherein said corrugated shape of
the plunging portion is continued in the portion of transition and/or in
the connecting portion.
14. A driveshaft according to claim 1, wherein the plunging journal is
hollow.
15. A driveshaft according to claim 1, wherein the second joint part of the
other constant velocity joint includes a connecting journal which
constitutes an extension of its longitudinal axis and which engages the
connecting portion of the connecting shaft and is secured thereto.
16. A driveshaft according to claim 15, wherein the connecting journal
comprises a corrugated shape which is adapted to the corrugated shape of
the connecting portion and which serves to provide a non-rotating
connection between the connecting journal and the connecting portion.
17. A driveshaft according to claim 15, wherein the connecting journal is
secured to the connecting portion by clamping means.
18. A driveshaft according to claim 1, wherein the rolling contact members
are provided in the form of balls.
19. A driveshaft according to claim 1, wherein the running grooves of the
plunging journal are produced by a non-chip producing forming operation.
Description
BACKGROUND OF THE INVENTION
The invention relates to a driveshaft for use in a driveline to drive
wheels of a motor vehicle. The driveshaft has two constant velocity joints
each having a first joint part with connecting means to establish a
connection with a driving or driven part of the driveline. Each joint has
a second joint part. The two constant velocity joints are connected to one
another by a connecting shaft. The two joints are designed as constant
velocity fixed joints which enable only angular movements between their
two respective joint parts. The driveshaft also includes means for
enabling a change in the distance between the connecting means.
U.S. Pat. No. 4,950,206 issued Aug. 21, 1990, discloses a driveshaft
wherein the second joint part of one of the constant velocity joints is
extended in a sleeve-like way and includes a bore provided with running
grooves. The connecting shaft is inserted into the bore and, on its outer
face, it also includes running grooves arranged so as to correspond to
those of the second joint part. The opposed running grooves contain
rolling contact members in the form of balls. The axial movement of the
connecting shaft relative to the second joint part is limited by stops.
The connecting shaft is a solid shaft and designed to be integral with the
second joint part of the other constant velocity joint. Furthermore, it is
possible to assemble the connecting shaft from a thin-walled tube and two
journals, with one of the journals directly connected to the second joint
part of the other joint without the plunging facility.
In such an embodiment, the size of the constant velocity joint has to be
such that it is adapted to the cross-section of the plunging part, which,
with respect to diameter, is dimensioned to meet torque transmitting
requirements. This means that the diameter of the joint has to be greater
than that normally required for torque transmitting purposes. Furthermore,
the second joint part, which constitutes the inner part, in addition to
including space to accommodate the journal, is provided with a radial wall
thickness between the bore and inner running track, which takes account
the respective strength requirements.
DE 41 19 451 C2, issued Mar. 25, 1993, describes a jointed shaft intended
to be used as a steering shaft for motor vehicles. It consists of the
joints provided in the form of universal joints, and a plunging part. The
plunging part includes a two-rib tube. The two ribs form running grooves.
An inner part associated with two ball circulation guides offset by
180.degree. is inserted into the two-rib tube. Such a design is
complicated and expensive and requires a great deal of space to
accommodate the two ball circulation guides. With steering shafts, such
space is available. Furthermore, in the case of steering shafts, the mass
to be moved is of no great significance as the steering shaft is moved for
the purpose of the steering movement only and the resulting speeds are
extremely low.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a driveshaft which has a
driving function, especially to drive the wheels of a motor vehicle. The
driveshaft includes two constant velocity fixed joints and means for
enabling a change in the distance between the connecting means of the
constant velocity joints. Also, the shaft enables a smaller diameter of
the constant velocity joints, with the connecting shaft as light as
possible to keep the weight of the moved masses low.
In accordance with the invention, the objective is achieved by providing
one of the two joint parts with a plunging journal. The journal
longitudinal axis is identical to that of the associated second joint
part. The plunging journal, in its outer face, has a plurality of
circumferentially distributed first running grooves extending parallel to
the longitudinal axis. The connecting shaft is provided in the form of a
tube with a plunging portion which is movably entered by the plunging
journal. The cross-section of the plunging portion is corrugated, with an
outer corrugation peak and an outer corrugation valley alternating on the
outer circumference. The bore of the plunging portion includes second
running grooves which are positioned opposite the first running grooves of
the plunging journal and extend parallel to the longitudinal axis. The
second running grooves are arranged in an outer corrugation peak. The
first and second running grooves, one of each form a pair, receive a
plurality of rolling contact members arranged one behind the other along
the running groove.
The advantage of providing the plunging portion in the form of a tube with
a corrugated cross-section is that it is possible to select a relatively
thin-walled tube to accommodate the torque because the corrugated shape
leads to a high torque transmitting capacity. Furthermore, such an
embodiment is advantageous in that it reduces vibrations because, although
the corrugated tube shape results in a high degree of elasticity, it
causes the vibrations to be modulated. The critical shaft speed is moved
into a range which is outside the operating speed range. In the case of
driveshafts used as vehicle sideshafts for example and serving to transmit
the rotational movement from the axle differential to the wheels, the
driveshaft speeds amount to up to 2000 revolutions per minute. As a
result, the noise behavior is affected advantageously.
There exists a further advantage in that, due to the separate plunging
assembly, it is possible, for assembly purposes, to provide a longer
distance than required for normal operation in the assembled condition. In
this way, assembly of the driveshaft in the motor vehicle is also
facilitated. A further advantage as compared to driveshafts wherein one of
the joints is a plunging joint is that the torque transmitting capacity
can be improved of the joint accommodating the plunging movement.
Furthermore, during torque transmission and angular movements of a joint
designed as a plunging joint, the friction values and thus the plunging
resistance are higher than in those cases where the torque transmitting
function under angular movements and the function of accommodating
plunging movements, resulting from the angular movements and compression
of the vehicle, are associated with separate components.
Particularly advantageous strength conditions are achieved if the plunging
portion is manufactured by a non-chip producing forming operation. The
plunging portion is preferably produced by hammering or rolling using
correspondingly shaped hammering or pressure tools, or by drawing using a
drawing tool, starting from a round drawn or welded tube which is given
its corrugated shape by a non-chip forming operation.
By carrying out a non-chip producing cold forming operation on the part, it
is possible to achieve an increase in strength. Furthermore, it is
possible to achieve smooth surfaces which are particularly suitable for
the rolling movement of the rolling contact members.
According to a further embodiment, the rolling contact members associated
with all the running grooves are held in a cage. The cage is movable to a
limited extent relative to the plunging journal and the plunging portion
along the longitudinal axis. The advantage of this embodiment is the balls
are guided and during the occurring movements the cage is adjusted such
that rolling contact movement takes place between the plunging portion and
the plunging journal. The cage may be plastics and may be produced by
injection molding.
To limit the plunging movement, the plunging portion is provided with stops
which cooperate either with the rolling contact members and/or the cage.
The plunging portion may additionally be provided with a further plunging
stop. The plunging journal stopping thereagainst to limit the distance
which the plunging journal is inserted into the plunging portion. This may
be of significance, for example, from the assembly viewpoint.
In a preferred embodiment, one of the stops and/or the plunging stop form
part of an insert inserted into the plunging portion. In a further
embodiment of the invention, the plunging journal may be hollow. It is
provided with a through-bore.
Apart from comprising the plunging portion, the connecting shaft may
additionally be provided with a connecting portion to secure to the second
joint part of the other constant velocity joint. The connecting portion
may start directly from the plunging portion. However, there is also
proposed a portion of transition which is arranged between the plunging
portion and the connecting portion and whose cross-sectional shape, for
example, deviates from that of the plunging portion and/or of the
connecting portion.
The cross-section of the plunging portion is preferably increased relative
to that of the portion of transition and/or that of the connecting portion
in order to make available the space required to accommodate the rolling
contact members. The cross-section of the plunging journal is the critical
cross-section whose strength is such to withstand the transmitted torque.
The plunging portion may be designed accordingly.
The vibration behavior of the connecting shaft is advantageously affected
if the corrugated shape of the plunging portion is continued in the
portion of transition and/or the connecting portion.
The stops are preferably associated with an insert which is supported
against a shoulder formed, as a result of a cross-sectional reduction, in
the region of transition between the plunging portion and the adjoining
portion, the portion of transition or the connecting portion.
To provide a connection between the connecting shaft and the second joint
part of the other constant velocity joint, a connecting journal is
provided which constitutes an extension of the longitudinal axis of the
second joint part. The connecting journal engages the connecting portion
of the connecting shaft and is secured thereto. In a further embodiment,
the connecting journal includes a corrugated shape which is adapted to the
corrugated shape of the connecting portion. The corrugated shapes of the
connecting journal and connecting portion complement one another so that a
non-rotating connection is achieved between the two parts.
In yet a further embodiment, the connecting journal may be connected to the
connecting portion by clamping means.
The rolling contact members of the plunging part are preferably provided in
the form of balls.
The running grooves of the plunging journal, too, may be manufactured by a
non-chip producing forming operation. Their production may take place
simultaneously with the non-chip producing forming operation of the second
joint part, which serves, for example, to produce the running grooves of
the second joint parts and the functional faces thereof.
From the following detailed description taken in conjunction with the
accompanying drawings and subjoined claims, other objects and advantages
of the present invention will become apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
Two preferred embodiments of the invention and an example of arranging the
driveshaft in a motor vehicle are diagrammatically illustrated in the
drawing wherein:
FIG. 1 is a longitudinal section view through a driveshaft in accordance
with the invention, with the constant velocity joints being in an extended
position.
FIG. 2 is a section view along line II--II of FIG. 1.
FIG. 3 is a longitudinal section view of an alternative driveshaft
embodiment, with the plunging portion differing from that shown in FIG. 1,
however, the two joints to which the connecting shaft is attached are not
shown; only the journal serving to connect them is illustrated.
FIG. 4 is a schematic view of the drive concept of a front wheel drive
motor vehicle in which driveshafts in accordance with the invention are
used.
DETAILED DESCRIPTION OF THE DRAWINGS
The driveshaft 1 as shown in FIG. 1 includes a first constant velocity
joint 2 and second constant velocity joint 3. The two constant velocity
joints 2, 3 are constant velocity fixed joints which are connected to one
another by a connecting shaft 4. The two constant velocity joints 2, 3 are
basically identical; they only differ with respect to their connecting
means.
The first constant velocity joint 2 includes of a first joint part 5,
constituting the outer part, whose cavity accommodates a second joint part
6, constituting the inner part. Furthermore, the first joint part 5
includes connecting means 7 in the form of a connecting journal which has
a contact shoulder 8 against which rests a corresponding contact face of a
part to which the constant velocity joint 2 is to be connected.
The first joint part 5 of the first constant velocity joint 2 includes the
outer joint part 9. The outer joint part 9 is provided in the form of a
sheet metal part and includes outer running grooves 10. Also, joint 5
includes the connecting journal 7 having the contact shoulder 8. The outer
joint part 9 and the connecting journal 7 are connected to one another by
a weld 11.
The second joint part 6 is received in the outer joint part 9 in the form
of the inner part. On its outer face, it includes inner running grooves
12, with each inner running groove 12 positioned opposite an outer running
groove 10 of the outer joint part 9. Both grooves 10, 12, jointly,
accommodate a ball 13. The balls 13 of all pairs of outer running grooves
10 and inner running grooves 12 are guided in a joint cage 14 arranged
between the outer face of the second joint part 6 and the inner face of
the outer joint part 9. A connecting journal 15 is integrally connected to
the portion of the second joint part 6 which constitutes the inner part.
As the driveshaft 1 is shown in its extended position, the longitudinal
axes are identical of the first joint part 5, the second joint part 6 and
the connecting journal 15. The longitudinal axis has been given the
reference number 16. A convoluted boot 17 is also provided which covers
the space between the outer face of the outer joint part 9 and the outer
face of the connecting journal 15 so that the lubricant required to
lubricate the first constant velocity joint is retained in the joint
chamber.
The second constant velocity joint 3 includes a first joint part 19 which
constitute the outer part. A connecting means includes a flange 18 which
serves to connect the first joint part 19 to a driving or driven part of
the driveline of the motor vehicle.
The second joint part 20 is received in the cavity of the first joint part
19. The design of the second constant velocity joint 3 substantially
corresponds to that of the first constant velocity joint 2. Running
grooves and balls are included to transmit torque between the two joints.
The second joint part 20 of the second constant velocity joint 3 also
includes an integrally formed on journal provided in the form of a
plunging journal 21. The plunging journal outer face has circumferentially
distributed first running grooves 22. As the second constant velocity
joint 3 also assumes an extended position, the longitudinal axes of the
second joint part 20 and the first joint part 19 are identical with the
longitudinal axis 16 of the first constant velocity joint 2.
The first running grooves 22 of the plunging journal 21 serve to
accommodate rolling contact members in the form of balls 23. Several balls
23 are arranged one behind the other in the running grooves 22. The balls
23 of all first running grooves 22 are held in a joint cage 24.
The connecting shaft 4 includes the plunging portion 26 which cooperates
with the balls 23 arranged in the first running grooves 22 of the plunging
journal 21. The shaft further includes the portion of transition 27 and
the connecting portion 28 which is associated with the connecting journal
15 of the first constant velocity joint 2.
Between the outer face of the plunging portion 26 and the first joint part
19 of the second constant velocity joint 3, a convoluted boot 25 is
arranged to seal the joint interior and to close the space between the
plunging portion 26 and the plunging journal 21. The plunging portion 26
is provided in the form of a corrugated tube whose shape is obtained, for
example, by a non-chip producing forming operation, starting from a
cylindrical tube. The parts may be produced by drawing in a suitable
forming tool, by hammering in a suitable forming tool or by rolling under
the pressure of accordingly shaped pressure rollers. In its cross-section
as illustrated in FIG. 2, the plunging portion 26 includes outer
corrugation peaks 30 and outer corrugation valleys 31 arranged in an
alternating sequence. The outer corrugation peak 30, in the bore of the
plunging portion 26, is provided with a second running groove 29 arranged
opposite a first running groove 22 of the plunging journal 21. Both serve
to receive balls 23. In the bore of the plunging portion 26, near its end
facing the second constant velocity joint 3, an extraction stop 33 is
provided in the form of a securing ring. For this purpose, the plunging
portion 26 includes a recess. The extraction stop 33 cooperates with a
corresponding extraction stop 34 formed by the end face of the cage 24 and
limits the movement of the cage 24 in the direction of the second constant
velocity joint 3.
The plunging portion 26 is followed by the region of transition 27 which is
also tubular and also includes grooves in continuation of the running
grooves 29 and thus includes a corrugated cross-section. The portion of
transition 27 changes into the connecting portion 28. In this embodiment,
both have the same cross-sectional shape. However, their cross-section is
reduced as compared to that of the plunging portion 26, thereby producing
a shoulder 32 in the region of transition.
An insert 35 is inserted into the bore of the plunging portion 26, which
axially rests against the shoulder 32. The insert 35 includes a face which
forms an insertion stop 36 which cooperates with the insertion stop 37
facing away from the extraction stop 34 of the cage 24 and limits the
insertion movement of the cage 24 towards the first constant velocity
joint 2. Furthermore, the insert 35 includes a plunging stop 38 which,
when the plunging journal 21 is in the fully inserted condition, is
contacted by the end face 39 of the plunging journal 21. The end face 39
is designed as a stop face. However, the stop only serves to limit the
insertion movement during the assembly of the driveshaft 1.
The outer face 41 of the connecting journal 15 associated with the second
joint part 6 of the first constant velocity joint 2 is designed to match
the inner face of the bore 40 of the connecting portion 28 of the
connecting shaft 4. The journal 15 is shaped accordingly, with its
cross-section including indentations and raised portions so that a
non-rotating connection is achieved between the connecting journal 15 and
the connecting portion 28 of the connecting shaft 4 when the connecting
journal 15 is inserted into the bore 40.
Clamping means 42 is provided to axially fix the connecting shaft 4 and the
connecting journal 15. The clamping means 42 is covered by a cap 43 to
which the convoluted boot 17 is secured. The cap 43 is attached to the
outer face of the connecting shaft 4.
In the embodiment of the driveshaft 1a according to FIG. 3, the connecting
shaft shoulder formed in the region of the reduced cross-section of the
plunging portion 26 towards the portion of transition 27 serves directly
as an insertion stop 36a. The stop 36a is contacted by the stop face 37 of
the cage 24. Otherwise, the embodiment largely corresponds to FIGS. 1 and
2.
In the two embodiments according to FIGS. 1, 2 and 3 respectively, the
first running grooves 22 and second running grooves 29, in the direction
of the longitudinal axis 16, are longer than the cage 24. This enables a
rolling contact movement of the balls 23 in the first running grooves 22
and second running grooves 29. However, beyond the plunging distance
provided for a rolling contact movement, a further reserve distance may be
provided by means of which the connecting shaft 4 enables a change in the
connecting length L between the connecting means 7, 8 and 18,
respectively, of the two constant velocity joints 2, 3 for assembly of the
driveshaft 1 and 1a. The shortening facility must be such that the
connecting journal 7 may be inserted into an associated connecting bore of
a driving or driven component. Subsequently, the flange 18 of the second
constant velocity joint 3 may be moved into the necessary connecting
position to enable the joint 3 to be connected to a driving or driven part
of the driveline.
The driveshafts 1 and 1a according to FIGS. 1 to 3 are used in the
driveline of a motor vehicle 44 according to FIG. 4, for example, whose
rear wheels 47 associated with the rear axle 45 are driven. The front
wheels 46 are not driven. The driveshafts 1 and 1a serve to drive the rear
wheels 47, the driving action starting from the engine 48 and continuing
via the gearbox 49 and the rear axle differential 50.
There are provided two driveshafts 1 or 1a one of which is used to connect
the rear axle differential 50 to the left rear wheel 47 and the other one
to connect the rear axle differential 50 to the right rear wheel 47.
The driveshaft 1, 1a, by means of the connecting journal associated with
the first constant velocity joint, may be connected to the left rear wheel
47. The second constant velocity joint, by means of the associated
connecting flange, is connected to a corresponding output flange of the
rear axle differential 50 of the gearbox output end serving to drive the
left rear wheel 47.
While the above detailed description describes the preferred embodiment of
the present invention, the invention is susceptible to modification,
variation and alteration without deviating from the scope and fair meaning
of the subjoined claims.
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